All my circle sprites gets a messed up squarish mesh

So I’m trying to make some shapes glow, but when I tried to apply the (any) shader to circular objects like circles and polygons, I noticed that it’s totally off. Looking at the wireframe, the circle gets a square-ish looking form, and even rectangles aren’t accurate. I both tried importing the shapes2D free assets package and creating my own, but it seems the mesh gets screwed either way, and I really want this glow.

This is super noticeable in my context where my shapes are hollow. Example below:

Been searching around for an answer, but the only thread I found was unanswered. Appreciate all suggestions.

Updating my answer as this might help you. I came up with this after I did some research of my own. Essentially, Unity tries to create an outline for you based on the image, but you can override it.

Get to the sprites import settings. Click on the ‘Sprite Editor’ button. It should be in the middle below Generate Physics Shape. It should open the editor for the sprite. In the top right hand corner, there is a drop down button. Click on ‘Custom Outline’. In here, you can create the outline as you see fit.

You should be able to hit the generate button in the middle. It will start you off with a box around the whole sprite with 4 verts. Just drag those verts where you want them. To add more verts (which you will want to), just hover your mouse on the line inbetween 2 verts and left click drag. Make sure you hit ‘apply’ when you are done.

I made a pretty good circle outline this way. It’s a little work, but I think it should get you in the right direction.